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[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15 #include <time.h>
16 #include <fcntl.h>
17 #include <errno.h>
18 #include <stdlib.h>
19 #include <signal.h>
20 #include <limits.h>
21 #include <resolv.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <syslog.h>
25 #include <stdbool.h>
26 #include <sys/time.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30
31 #include <net/if.h>
32 #include <net/ethernet.h>
33
34 #include "odhcp6c.h"
35 #include "md5.h"
36
37
38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
39 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
40 #define DHCPV6_CLIENT_PORT 546
41 #define DHCPV6_SERVER_PORT 547
42 #define DHCPV6_DUID_LLADDR 3
43 #define DHCPV6_REQ_DELAY 1
44
45
46 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
47 const uint8_t transaction[3], enum dhcpv6_msg type);
48
49 static uint32_t dhcpv6_parse_ia(void *opt, void *end);
50
51 static reply_handler dhcpv6_handle_reply;
52 static reply_handler dhcpv6_handle_advert;
53 static reply_handler dhcpv6_handle_rebind_reply;
54 static reply_handler dhcpv6_handle_reconfigure;
55 static int dhcpv6_commit_advert(void);
56
57
58
59 // RFC 3315 - 5.5 Timeout and Delay values
60 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
61 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, "<POLL>",
62 dhcpv6_handle_reconfigure, NULL},
63 [DHCPV6_MSG_SOLICIT] = {true, 1, 3600, "SOLICIT",
64 dhcpv6_handle_advert, dhcpv6_commit_advert},
65 [DHCPV6_MSG_REQUEST] = {true, 30, 10, "REQUEST",
66 dhcpv6_handle_reply, NULL},
67 [DHCPV6_MSG_RENEW] = {false, 10, 600, "RENEW",
68 dhcpv6_handle_reply, NULL},
69 [DHCPV6_MSG_REBIND] = {false, 10, 600, "REBIND",
70 dhcpv6_handle_rebind_reply, NULL},
71 [DHCPV6_MSG_RELEASE] = {false, 1, 600, "RELEASE", NULL, NULL},
72 [DHCPV6_MSG_DECLINE] = {false, 1, 3, "DECLINE", NULL, NULL},
73 [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, "INFOREQ",
74 dhcpv6_handle_reply, NULL},
75 };
76
77
78 // Sockets
79 static int sock = -1;
80 static int ifindex = -1;
81 static int64_t t1 = 0, t2 = 0, t3 = 0;
82
83 // IA states
84 static int request_prefix = -1;
85 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE;
86 static bool accept_reconfig = false;
87
88 // Reconfigure key
89 static uint8_t reconf_key[16];
90
91
92
93 int init_dhcpv6(const char *ifname, int request_pd)
94 {
95 request_prefix = request_pd;
96
97 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
98
99 // Detect interface
100 struct ifreq ifr;
101 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
102 if (ioctl(sock, SIOCGIFINDEX, &ifr))
103 return -1;
104 ifindex = ifr.ifr_ifindex;
105
106 // Create client DUID
107 size_t client_id_len;
108 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
109 if (client_id_len == 0) {
110 ioctl(sock, SIOCGIFHWADDR, &ifr);
111 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
112 DHCPV6_DUID_LLADDR, 0, 1};
113 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
114
115 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
116 struct ifreq ifs[100], *ifp, *ifend;
117 struct ifconf ifc;
118 ifc.ifc_req = ifs;
119 ifc.ifc_len = sizeof(ifs);
120
121 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
122 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
123 // If our interface doesn't have an address...
124 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
125 for (ifp = ifc.ifc_req; ifp < ifend &&
126 !memcmp(&duid[8], zero, 6); ifp++) {
127 memcpy(ifr.ifr_name, ifp->ifr_name,
128 sizeof(ifr.ifr_name));
129 ioctl(sock, SIOCGIFHWADDR, &ifr);
130 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
131 ETHER_ADDR_LEN);
132 }
133 }
134
135 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
136 }
137
138 // Create ORO
139 uint16_t oro[] = {
140 htons(DHCPV6_OPT_SIP_SERVER_D),
141 htons(DHCPV6_OPT_SIP_SERVER_A),
142 htons(DHCPV6_OPT_DNS_SERVERS),
143 htons(DHCPV6_OPT_DNS_DOMAIN),
144 htons(DHCPV6_OPT_NTP_SERVER),
145 htons(DHCPV6_OPT_SIP_SERVER_A),
146 htons(DHCPV6_OPT_AFTR_NAME),
147 htons(DHCPV6_OPT_PD_EXCLUDE),
148 htons(DHCPV6_OPT_PREFIX_CLASS),
149 };
150 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
151
152
153 // Configure IPv6-options
154 int val = 1;
155 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
156 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
157 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
158
159 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
160 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
161 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
162 return -1;
163
164 return 0;
165 }
166
167
168 void dhcpv6_set_ia_na_mode(enum odhcp6c_ia_mode mode)
169 {
170 na_mode = mode;
171 }
172
173
174 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
175 {
176 // Build FQDN
177 char fqdn_buf[256];
178 gethostname(fqdn_buf, sizeof(fqdn_buf));
179 struct {
180 uint16_t type;
181 uint16_t len;
182 uint8_t flags;
183 uint8_t data[256];
184 } fqdn;
185 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
186 sizeof(fqdn.data), NULL, NULL);
187 fqdn.type = htons(DHCPV6_OPT_FQDN);
188 fqdn.len = htons(fqdn_len - 4);
189 fqdn.flags = 0;
190
191
192 // Build Client ID
193 size_t cl_id_len;
194 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
195
196 // Get Server ID
197 size_t srv_id_len;
198 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
199
200 // Build IA_PDs
201 size_t ia_pd_entries, ia_pd_len = 0;
202 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
203 ia_pd_entries /= sizeof(*e);
204 struct dhcpv6_ia_hdr hdr_ia_pd = {
205 htons(DHCPV6_OPT_IA_PD),
206 htons(sizeof(hdr_ia_pd) - 4),
207 1, 0, 0
208 };
209
210
211 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
212 for (size_t i = 0; i < ia_pd_entries; ++i) {
213 uint8_t ex_len = 0;
214 if (e[i].priority > 0)
215 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
216
217 struct dhcpv6_ia_prefix p = {
218 .type = htons(DHCPV6_OPT_IA_PREFIX),
219 .len = htons(sizeof(p) - 4U + ex_len),
220 .prefix = e[i].length,
221 .addr = e[i].target
222 };
223
224 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
225 ia_pd_len += sizeof(p);
226
227 if (ex_len) {
228 ia_pd[ia_pd_len++] = 0;
229 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
230 ia_pd[ia_pd_len++] = 0;
231 ia_pd[ia_pd_len++] = ex_len - 4;
232 ia_pd[ia_pd_len++] = e[i].priority;
233
234 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
235 excl >>= (64 - e[i].priority);
236 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
237
238 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
239 ia_pd[ia_pd_len + i] = excl & 0xff;
240 ia_pd_len += ex_len - 5;
241 }
242 }
243
244 struct dhcpv6_ia_prefix pref = {
245 .type = htons(DHCPV6_OPT_IA_PREFIX),
246 .len = htons(25), .prefix = request_prefix
247 };
248 if (request_prefix > 0 && ia_pd_len == 0 &&
249 (type == DHCPV6_MSG_SOLICIT ||
250 type == DHCPV6_MSG_REQUEST)) {
251 ia_pd = (uint8_t*)&pref;
252 ia_pd_len = sizeof(pref);
253 }
254 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
255
256 // Build IA_NAs
257 size_t ia_na_entries, ia_na_len = 0;
258 void *ia_na = NULL;
259 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
260 ia_na_entries /= sizeof(*e);
261
262 struct dhcpv6_ia_hdr hdr_ia_na = {
263 htons(DHCPV6_OPT_IA_NA),
264 htons(sizeof(hdr_ia_na) - 4),
265 1, 0, 0
266 };
267
268 struct dhcpv6_ia_addr pa[ia_na_entries];
269 for (size_t i = 0; i < ia_na_entries; ++i) {
270 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
271 pa[i].len = htons(sizeof(pa[i]) - 4U);
272 pa[i].addr = e[i].target;
273 pa[i].preferred = 0;
274 pa[i].valid = 0;
275 }
276
277 ia_na = pa;
278 ia_na_len = sizeof(pa);
279 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
280
281 // Reconfigure Accept
282 struct {
283 uint16_t type;
284 uint16_t length;
285 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
286
287 // Request Information Refresh
288 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
289
290 // Prepare Header
291 size_t oro_len;
292 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
293 struct {
294 uint8_t type;
295 uint8_t trid[3];
296 uint16_t elapsed_type;
297 uint16_t elapsed_len;
298 uint16_t elapsed_value;
299 uint16_t oro_type;
300 uint16_t oro_len;
301 } hdr = {
302 type, {trid[0], trid[1], trid[2]},
303 htons(DHCPV6_OPT_ELAPSED), htons(2),
304 htons((ecs > 0xffff) ? 0xffff : ecs),
305 htons(DHCPV6_OPT_ORO), htons(oro_len),
306 };
307
308 struct iovec iov[] = {
309 {&hdr, sizeof(hdr)},
310 {oro, oro_len},
311 {&oro_refresh, 0},
312 {cl_id, cl_id_len},
313 {srv_id, srv_id_len},
314 {&reconf_accept, sizeof(reconf_accept)},
315 {&fqdn, fqdn_len},
316 {&hdr_ia_na, sizeof(hdr_ia_na)},
317 {ia_na, ia_na_len},
318 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
319 {ia_pd, ia_pd_len},
320 };
321
322 size_t cnt = ARRAY_SIZE(iov);
323 if (type == DHCPV6_MSG_INFO_REQ) {
324 cnt = 5;
325 iov[2].iov_len = sizeof(oro_refresh);
326 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
327 } else if (!request_prefix) {
328 cnt = 9;
329 }
330
331 // Disable IAs if not used
332 if (type != DHCPV6_MSG_REQUEST && type != DHCPV6_MSG_SOLICIT) {
333 iov[5].iov_len = 0;
334 if (ia_na_len == 0)
335 iov[7].iov_len = 0;
336 if (ia_pd_len == 0)
337 iov[9].iov_len = 0;
338 }
339
340 if (na_mode == IA_MODE_NONE)
341 iov[7].iov_len = 0;
342
343 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
344 0, ALL_DHCPV6_RELAYS, ifindex};
345 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
346
347 sendmsg(sock, &msg, 0);
348 }
349
350
351 static int64_t dhcpv6_rand_delay(int64_t time)
352 {
353 int random;
354 odhcp6c_random(&random, sizeof(random));
355 return (time * (random % 1000)) / 10000;
356 }
357
358
359 int dhcpv6_request(enum dhcpv6_msg type)
360 {
361 uint8_t buf[1536];
362 uint32_t timeout = UINT32_MAX;
363 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
364
365 if (retx->delay) {
366 struct timespec ts = {0, 0};
367 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
368 nanosleep(&ts, NULL);
369 }
370
371 if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
372 timeout = 3;
373 else if (type == DHCPV6_MSG_UNKNOWN)
374 timeout = t1;
375 else if (type == DHCPV6_MSG_RENEW)
376 timeout = (t2 > t1) ? t2 - t1 : 0;
377 else if (type == DHCPV6_MSG_REBIND)
378 timeout = (t3 > t2) ? t3 - t2 : 0;
379
380 if (timeout == 0)
381 return -1;
382
383 syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, timeout);
384
385 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
386
387 // Generate transaction ID
388 uint8_t trid[3] = {0, 0, 0};
389 if (type != DHCPV6_MSG_UNKNOWN)
390 odhcp6c_random(trid, sizeof(trid));
391 ssize_t len = -1;
392 int64_t rto = 0;
393
394 do {
395 rto = (rto == 0) ? (retx->init_timeo * 1000 +
396 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
397 (2 * rto + dhcpv6_rand_delay(rto));
398
399 if (rto >= retx->max_timeo * 1000)
400 rto = retx->max_timeo * 1000 +
401 dhcpv6_rand_delay(retx->max_timeo * 1000);
402
403 // Calculate end for this round and elapsed time
404 uint64_t round_end = round_start + rto;
405 elapsed = round_start - start;
406
407 // Don't wait too long
408 if (round_end - start > timeout * 1000)
409 round_end = timeout * 1000 + start;
410
411 // Built and send package
412 if (type != DHCPV6_MSG_UNKNOWN)
413 dhcpv6_send(type, trid, elapsed / 10);
414
415 // Receive rounds
416 for (; len < 0 && round_start < round_end;
417 round_start = odhcp6c_get_milli_time()) {
418 // Check for pending signal
419 if (odhcp6c_signal_process())
420 return -1;
421
422 // Set timeout for receiving
423 uint64_t t = round_end - round_start;
424 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
425 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
426 &timeout, sizeof(timeout));
427
428 // Receive cycle
429 len = recv(sock, buf, sizeof(buf), 0);
430
431 if (!dhcpv6_response_is_valid(buf, len, trid, type))
432 len = -1;
433
434 if (len > 0) {
435 uint8_t *opt = &buf[4];
436 uint8_t *opt_end = opt + len - 4;
437
438 round_start = odhcp6c_get_milli_time();
439 elapsed = round_start - start;
440 syslog(LOG_NOTICE, "Got a valid reply after "
441 "%ums", (unsigned)elapsed);
442
443 if (retx->handler_reply)
444 len = retx->handler_reply(
445 type, opt, opt_end);
446
447 if (round_end - round_start > 1000)
448 round_end = 1000 + round_start;
449 }
450 }
451
452 // Allow
453 if (retx->handler_finish)
454 len = retx->handler_finish();
455 } while (len < 0 && elapsed / 1000 < timeout);
456
457 return len;
458 }
459
460
461 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
462 const uint8_t transaction[3], enum dhcpv6_msg type)
463 {
464 const struct dhcpv6_header *rep = buf;
465 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
466 transaction, sizeof(rep->tr_id)))
467 return false; // Invalid reply
468
469 if (type == DHCPV6_MSG_SOLICIT) {
470 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
471 rep->msg_type != DHCPV6_MSG_REPLY)
472 return false;
473 } else if (type == DHCPV6_MSG_UNKNOWN) {
474 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
475 return false;
476 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
477 return false;
478 }
479
480 uint8_t *end = ((uint8_t*)buf) + len, *odata;
481 uint16_t otype, olen;
482 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
483
484 size_t client_id_len, server_id_len;
485 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
486 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
487
488 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
489 if (otype == DHCPV6_OPT_CLIENTID) {
490 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
491 &odata[-4], client_id, client_id_len);
492 } else if (otype == DHCPV6_OPT_SERVERID) {
493 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
494 &odata[-4], server_id, server_id_len);
495 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
496 sizeof(struct dhcpv6_auth_reconfigure)) {
497 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
498 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
499 continue;
500
501 md5_state_t md5;
502 uint8_t serverhash[16], secretbytes[16], hash[16];
503 memcpy(serverhash, r->key, sizeof(serverhash));
504 memset(r->key, 0, sizeof(r->key));
505 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
506
507 for (size_t i = 0; i < sizeof(secretbytes); ++i)
508 secretbytes[i] ^= 0x36;
509
510 md5_init(&md5);
511 md5_append(&md5, secretbytes, sizeof(secretbytes));
512 md5_append(&md5, buf, len);
513 md5_finish(&md5, hash);
514
515 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
516 secretbytes[i] ^= 0x36;
517 secretbytes[i] ^= 0x5c;
518 }
519
520 md5_init(&md5);
521 md5_append(&md5, secretbytes, sizeof(secretbytes));
522 md5_append(&md5, hash, 16);
523 md5_finish(&md5, hash);
524
525 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
526 }
527 }
528
529 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
530 return false;
531
532 return clientid_ok && (serverid_ok || server_id_len == 0);
533 }
534
535
536 int dhcpv6_poll_reconfigure(void)
537 {
538 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
539 if (ret != -1)
540 ret = dhcpv6_request(ret);
541
542 return ret;
543 }
544
545
546 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
547 const void *opt, const void *end)
548 {
549 // TODO: should verify the reconfigure message
550 uint16_t otype, olen;
551 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
552 dhcpv6_for_each_option(opt, end, otype, olen, odata)
553 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
554 odata[0] == DHCPV6_MSG_RENEW ||
555 odata[0] == DHCPV6_MSG_INFO_REQ))
556 msg = odata[0];
557
558 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
559 return msg;
560 }
561
562
563 // Collect all advertised servers
564 static int dhcpv6_handle_advert(_unused enum dhcpv6_msg orig,
565 const void *opt, const void *end)
566 {
567 uint16_t olen, otype;
568 uint8_t *odata;
569 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}};
570
571 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
572 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
573 memcpy(cand.duid, odata, olen);
574 cand.duid_len = olen;
575 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
576 && odata[1] == DHCPV6_NoAddrsAvail) {
577 if (na_mode == IA_MODE_FORCE) {
578 return -1;
579 } else {
580 cand.has_noaddravail = true;
581 cand.preference -= 1000;
582 }
583 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
584 && odata[1] == DHCPV6_NoPrefixAvail) {
585 cand.preference -= 2000;
586 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
587 cand.preference >= 0) {
588 cand.preference = odata[0];
589 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
590 cand.wants_reconfigure = true;
591 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
592 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
593 uint8_t *oend = odata + olen, *d;
594 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
595 if (otype == DHCPV6_OPT_IA_PREFIX)
596 cand.preference += 2000;
597 else if (otype == DHCPV6_OPT_STATUS &&
598 olen >= 2 && d[0] == 0 &&
599 d[1] == DHCPV6_NoPrefixAvail)
600 cand.preference -= 2000;
601 }
602 }
603 }
604
605 if (cand.duid_len > 0)
606 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
607
608 return -1;
609 }
610
611
612 static int dhcpv6_commit_advert(void)
613 {
614 size_t cand_len;
615 struct dhcpv6_server_cand *c = NULL, *cand =
616 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
617
618 bool retry = false;
619 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
620 if (cand[i].has_noaddravail)
621 retry = true; // We want to try again
622
623 if (!c || c->preference < cand[i].preference)
624 c = &cand[i];
625 }
626
627 if (retry && na_mode == IA_MODE_TRY) {
628 // We give it a second try without the IA_NA
629 na_mode = IA_MODE_NONE;
630 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
631 }
632
633 if (c) {
634 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
635 htons(c->duid_len)};
636 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
637 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
638 accept_reconfig = c->wants_reconfigure;
639 }
640
641 odhcp6c_clear_state(STATE_SERVER_CAND);
642
643 if (!c)
644 return -1;
645 else if (request_prefix || na_mode != IA_MODE_NONE)
646 return DHCPV6_STATEFUL;
647 else
648 return DHCPV6_STATELESS;
649 }
650
651
652 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
653 const void *opt, const void *end)
654 {
655 dhcpv6_handle_advert(orig, opt, end);
656 if (dhcpv6_commit_advert() < 0) {
657 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
658 return -1;
659 }
660
661 return dhcpv6_handle_reply(orig, opt, end);
662 }
663
664
665 static int dhcpv6_handle_reply(enum dhcpv6_msg orig,
666 const void *opt, const void *end)
667 {
668 uint8_t *odata;
669 uint16_t otype, olen;
670
671 odhcp6c_expire();
672
673 if (orig == DHCPV6_MSG_UNKNOWN) {
674 static time_t last_update = 0;
675 time_t now = odhcp6c_get_milli_time() / 1000;
676
677 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
678 last_update = now;
679
680 t1 -= elapsed;
681 t2 -= elapsed;
682 t3 -= elapsed;
683
684 if (t1 < 0)
685 t1 = 0;
686
687 if (t2 < 0)
688 t2 = 0;
689
690 if (t3 < 0)
691 t3 = 0;
692 } else {
693 t1 = t2 = t3 = UINT32_MAX;
694 }
695
696 if (opt) {
697 odhcp6c_clear_state(STATE_DNS);
698 odhcp6c_clear_state(STATE_SEARCH);
699 odhcp6c_clear_state(STATE_SNTP_IP);
700 odhcp6c_clear_state(STATE_SNTP_FQDN);
701 odhcp6c_clear_state(STATE_SIP_IP);
702 odhcp6c_clear_state(STATE_SIP_FQDN);
703 odhcp6c_clear_state(STATE_AFTR_NAME);
704 }
705
706 // Parse and find all matching IAs
707 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
708 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
709 && olen > sizeof(struct dhcpv6_ia_hdr)) {
710 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
711 uint32_t l_t1 = ntohl(ia_hdr->t1);
712 uint32_t l_t2 = ntohl(ia_hdr->t2);
713
714 // Test ID and T1-T2 validity
715 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
716 continue;
717
718 bool error = false;
719 uint16_t stype, slen;
720 uint8_t *sdata;
721 // Test status and bail if error
722 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
723 stype, slen, sdata)
724 if (stype == DHCPV6_OPT_STATUS && slen >= 2 &&
725 (sdata[0] || sdata[1]))
726 error = true;
727
728 if (error)
729 continue;
730
731 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
732
733 if (!l_t1)
734 l_t1 = 300;
735
736 if (!l_t2)
737 l_t2 = 600;
738
739 if (n < t3)
740 t3 = n;
741
742 // Update times
743 if (l_t1 > 0 && t1 > l_t1)
744 t1 = l_t1;
745
746 if (l_t2 > 0 && t2 > l_t2)
747 t2 = l_t2;
748
749 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
750 if (olen % 16 == 0)
751 odhcp6c_add_state(STATE_DNS, odata, olen);
752 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
753 odhcp6c_add_state(STATE_SEARCH, odata, olen);
754 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
755 uint16_t stype, slen;
756 uint8_t *sdata;
757 // Test status and bail if error
758 dhcpv6_for_each_option(odata, odata + olen,
759 stype, slen, sdata) {
760 if (slen == 16 && (stype == NTP_MC_ADDR ||
761 stype == NTP_SRV_ADDR))
762 odhcp6c_add_state(STATE_SNTP_IP,
763 sdata, slen);
764 else if (slen > 0 && stype == NTP_SRV_FQDN)
765 odhcp6c_add_state(STATE_SNTP_FQDN,
766 sdata, slen);
767 }
768 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
769 if (olen == 16)
770 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
771 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
772 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
773 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
774 uint32_t refresh = ntohl(*((uint32_t*)odata));
775 if (refresh < (uint32_t)t1)
776 t1 = refresh;
777 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
778 sizeof(struct dhcpv6_auth_reconfigure)) {
779 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
780 if (r->protocol == 3 && r->algorithm == 1 &&
781 r->reconf_type == 1)
782 memcpy(reconf_key, r->key, sizeof(r->key));
783 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
784 size_t cur_len;
785 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
786 if (cur_len == 0)
787 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
788 } else if (otype != DHCPV6_OPT_CLIENTID &&
789 otype != DHCPV6_OPT_SERVERID) {
790 odhcp6c_add_state(STATE_CUSTOM_OPTS,
791 &odata[-4], olen + 4);
792 }
793 }
794
795 return true;
796 }
797
798
799 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
800 {
801 uint32_t timeout = UINT32_MAX; // Minimum timeout
802 uint16_t otype, olen;
803 uint8_t *odata;
804
805 // Update address IA
806 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
807 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT,
808 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0};
809
810 if (otype == DHCPV6_OPT_IA_PREFIX) {
811 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
812 if (olen + 4U < sizeof(*prefix))
813 continue;
814
815 entry.valid = ntohl(prefix->valid);
816 entry.preferred = ntohl(prefix->preferred);
817
818 if (entry.preferred > entry.valid)
819 continue;
820
821 entry.length = prefix->prefix;
822 entry.target = prefix->addr;
823 uint16_t stype, slen;
824 uint8_t *sdata;
825
826 // Find prefix class, if any
827 dhcpv6_for_each_option(&prefix[1], odata + olen,
828 stype, slen, sdata)
829 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
830 entry.prefix_class = ntohs(*((uint16_t*)sdata));
831
832 // Parse PD-exclude
833 bool ok = true;
834 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
835 odata + olen, stype, slen, sdata) {
836 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
837 continue;
838
839 uint8_t elen = sdata[0];
840 if (elen > 64)
841 elen = 64;
842
843 if (elen <= 32 || elen <= entry.length) {
844 ok = false;
845 continue;
846 }
847
848
849 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
850 if (slen <= bytes) {
851 ok = false;
852 continue;
853 }
854
855 uint32_t exclude = 0;
856 do {
857 exclude = exclude << 8 | sdata[bytes];
858 } while (--bytes);
859
860 exclude >>= 8 - ((elen - entry.length) % 8);
861 exclude <<= 64 - elen;
862
863 // Abusing router & priority fields for exclusion
864 entry.router = entry.target;
865 entry.router.s6_addr32[1] |= htonl(exclude);
866 entry.priority = elen;
867 }
868
869 if (ok)
870 odhcp6c_update_entry(STATE_IA_PD, &entry);
871
872 entry.priority = 0;
873 memset(&entry.router, 0, sizeof(entry.router));
874 } else if (otype == DHCPV6_OPT_IA_ADDR) {
875 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
876 if (olen + 4U < sizeof(*addr))
877 continue;
878
879 entry.preferred = ntohl(addr->preferred);
880 entry.valid = ntohl(addr->valid);
881
882 if (entry.preferred > entry.valid)
883 continue;
884
885 entry.length = 128;
886 entry.target = addr->addr;
887
888 odhcp6c_update_entry(STATE_IA_NA, &entry);
889 }
890
891 if (entry.valid > 0 && timeout > entry.valid)
892 timeout = entry.valid;
893 }
894
895 return timeout;
896 }
Openwrt DHCPv6 Client